Isomeric Triptycene Triquinones as Universal Cathode Materials for High Energy Alkali Metal Batteries

Organic electrode materials have been extensively researched for alkali metal batteries such as Li, Na, and K batteries due to their unique redox mechanism independent of types of charge-carrying ions and flexible intermolecular structures facilitating the insertion of bulky metal-ions. This study presents an ortho-isomer of triptycene tribenzoquinone (o-TT) as a universal organic cathode material for alkali metal batteries. To elevate the redox potentials of previously reported triptycene tribenzoquinone (TT) without sacrificing its large specific capacity (similar to 386 mAh g(-1)), the structural isomers of benzoquinone units in the TT molecule were designed by changing their carbonyl group position from para- to ortho-position. Due to multi-electron redox reactions and the elevated redox potentials, o-TT shows high energy densities of 945, 767, and 597 Wh kg(-1) in Li, Na, and K cells, respectively. Finally, its cycle stability is significantly improved by fabricating composite electrodes with disordered mesoporous carbon (DOMC).

Automated summary

Organic electrode materials are suitable for alkali metal batteries due to their unique redox mechanism and flexible molecular structure. In this study, an ortho-isomer of triptycene tribenzoquinone (o-TT) is presented as a universal organic cathode material for alkali metal batteries. By changing the position of the carbonyl group in the benzoquinone units, the redox potentials of TT are enhanced without sacrificing its large specific capacity. o-TT exhibits high energy densities in Li, Na, and K cells due to multi-electron redox reactions and elevated redox potentials. Finally, the cycle stability of o-TT is significantly improved by fabricating composite electrodes with disordered mesoporous carbon (DOMC).